I would like somebody to explain the difference between elevons and v-tail.

As far as I can tell they function the same way in regard to joystick input. The different name is because the elevons are at the wings or am I missing something?

The reason I ask is because I am considering of bying a Tx-Rx system and would like the Tx to have the above functions so I can fly my planes.

Thanks.

Vee-tail when used for turning and elevons are the same in function.
When I have a plane without ailerons, and no ground steering needed, I use the elevon function for the vee-tail controls, turning on the right stick.
When I have a vee-tailed plane which takes off from the ground, I use the v-tail function on the rudder-vators which use channels 2 and 4, 2 for elevator on the right stick, 4 for turning on the left stick, with a seperate servo or hookup for the ground steering on channel 4, and the 1->4 MIX to get the right stick for the turning function in the air.
Most 6-channel radios provide all 3; elevon, v-tail and 1->4 MIX.

Elevons: As you said, elevators and ailerons on the wing combined in two rudder-surfaces and requiring a mixing. Usually no elevator in addition on the plane, but sometimes combined with canards on the front of the fuse... Typical you find this on deltaes and flying wings.

V-tail: Rudder and elevator, combined in two rudder-surfaces at the TAIL. Often you find ailerons in addition on the wings... Usually you find this on sailplanes.

Elevon mixing takes your aileron and elevator inputs and mixes them together to control two surfaces. V-tail mixing takes your elevator and rudder inputs and mixes them together to control two surfaces. This allows a single pair of control surafaces to act as an aileron & elevator or elevator & rudder simulataneously.

V-tail is also referred to as "ruddervator," though not very often, due to the distinctive shape of the tail (big hint: It's a "V" )

Exactly.

On a Hitec or Futaba radio, Elevons mix Channels 1 and 2. V tail mixes channel 1 and 4.

Elevons are primarily used on flying wings, such as the Zagi planes, or delta wings, such as the micro jet and twin jets.

V tails are very popular on sailplanes and some parkflyers.